1. Field of the Invention
The present invention relates to hinge assemblies and, particularly, to a hinge assembly for foldable electronic devices, such as mobile telephones, electronic notebooks, and so on.
2. Discussion of the Related Art
With the development of wireless communication and information processing technologies, portable electronic devices such as mobile telephones and electronic notebooks are now in widespread use. These electronic devices enable consumers to enjoy high technology services anytime and anywhere. Consumers particularly favor foldable electronic devices due to their convenience and ease of storage.
Generally, foldable electronic devices have most of the electronics in one housing, called the body. The other housing, called the cover, normally contains fewer electronic components than the body. Other foldable electronic devices have all the electronics in the body, with the cover containing no electronics. Various types of hinge assemblies are used to join a body and a cover of a foldable electronic device, so that the cover can unfold up from and fold down upon the body. Manufacturers are constantly seeking to reduce the volume, size and weight of portable foldable electronic devices. Thus, it is desirable that the hinge assembly coupling the main housing with the cover is modularized and miniaturized. A modularized hinge assembly has moving parts such as a cam member, a cam follower, a shaft, and a spring, held together in a unified structure. Either the cam member or the cam follower directly contacts the spring. The structure is easily and quickly attached to the main housing and the cover during mass production. The cam member and the cam follower always contact each other under the force of the spring.
Although suitable for some foldable electronic devices, sliding friction is produced between the cam member and the cam follower because of the relative rotation therebetween. This friction wastes energy (i.e., making opening and/or closing of the device more difficult) and causes abrasion of the cam member and the cam follower. The worn surface can further add to the friction therebetween and may eventually lead to premature malfunction or failure of the hinge assembly. In addition, the hinge assembly has many components, thus complicating manufacture. Moreover, during the process of opening and closing of a flip cover of the foldable electronic device, one of the cam member and the cam follower is quickly rotated under the spring force of the spring, which produces a large impact on the flip cover. Damage caused by these impacts may eventually lead to premature malfunction or failure of the foldable electronic device.
What is needed, therefore, is a hinge assembly which has a relatively simple configuration, which can be produced at low cost, and which has a low amount of friction associated therewith.